Exemplary conventional sliding materials required to have a low friction include sliding members having a substrate with a surface layer having a fluororesin laminated or coated thereon and sliding members having a substrate and a fabric such as woven fabric, knitted fabric, or nonwoven fabric disposed thereon, the fabric being the one prepared by using a fluororesin fiber.
However, the fluororesin laminate and coating are insufficient in the fluororesin film thickness, and they are also non-adherent and, therefore, the laminate and the coating have the drawback that they are likely to be peeled off the substrate.
Meanwhile, also disclosed is a technology wherein a fluororesin fiber fabric is used in combination with the sliding member, which is the substrate. For example, Japanese Unexamined Patent Publication (Kokai) No. 2010-164999 discloses a sliding member used as a pressure-applying low-friction sliding member in a toner fixer incorporated in an image forming apparatus such as a photocopier or printer wherein a porous fluororesin woven fabric is used on the surface of the sliding member. Japanese Unexamined Patent Publication (Kokai) No. 2008-150724 discloses a fabric containing a fluorine based fiber mounted on the surface of the vibration-isolating rubber in an automobile stabilizer bar to thereby reduce the friction of the vibration-isolating rubber.
Another known production technology is integration of a woven fabric or a fiber material with a resin member although that technology is not for the sliding member. For example, Japanese Unexamined Patent Publication (Kokai) No. 59-095126 discloses a production of a laminate produced by injecting a thermoplastic resin on the rear surface of a knitted or woven fiber fabric or the like to form the substrate.
As described above in Japanese Unexamined Patent Publication (Kokai) No. 2010-164999 and Japanese Unexamined Patent Publication (Kokai) No. 2008-150724, low friction sliding members wherein the surface of the substrate sliding member is covered with a fluororesin fabric have been disclosed. However, those members are insufficient in the adhesion and securing to the substrate due to the non-sticky nature of the fluorine fiber.
In Japanese Unexamined Patent Publication (Kokai) No. 2010-164999, two or more engagement holes are formed in the fluorine fiber woven fabric, and the substrate is provided with engagement means at positions corresponding to the engagement holes to thereby engage the fluorine fiber woven fabric to the surface of the sliding member. In Japanese Unexamined Patent Publication (Kokai) No. 2008-150724, adhesion to the vibration-isolating rubber is improved by incorporating thermally fusible fibers in the surface of the fabric containing the fluorine-based fibers on the surface opposite to the surface containing the fluorine-based fibers.
As described above, various procedures have been proposed to improve adhesion in securing the inherently non-sticky fluorine fiber fabric to the surface of the substrate sliding member. However, these proposals have been insufficient in improving the adhesion to maintain durability and abrasion resistance under the strong force applied during the sliding. There is also the problem of time, effort, and cost.
Meanwhile, Japanese Unexamined Patent Publication (Kokai) No. 59-095126 uses a thermoplastic resin for both of the fiber woven or knitted fabric (the surface) and the molding material (the substrate), and the substrate material is injected to the rear surface of the surface layer to form the substrate while the front surface layer is softened by heating to realize the integration by thermal fusion. In this process, firm adhesion is enabled by using the same material for both the front surface layer and the substrate. However, this does not provide a low friction material such as fluororesin fiber on the front surface layer in addition to the thermoplastic resin, and does not achieve the low friction and the long life as a sliding member.
In view of the situation as described above, it could be helpful to provide a low friction composite sliding member exhibiting excellent adhesion property by integrating a resin sliding member (the substrate) and a low friction fiber woven fabric.